Bantuan AS kepada MesirEgypt has received $28bn in assistance since 1975, according to the US Agency for International Development. While USAID's website says the funds have gone to programs devoted to health, trade and education – among other things – most US aid goes to Egypt's military.

Egypt receives close to $2bn in economic and military aid every year, making it the second largest recipient of US foreign assistance after Israel. Of that, $1.3bn is devoted to military assistance, according to the Congressional Research Service, the public policy arm of the US congress.

One third of Egypt's military aid is used to upgrade its weapons systems - in essence to replace older Soviet weapons with US arms, according to a CRS report.

During the past four days of protests, it's been widely reported that tear gas canisters fired at protesters are stamped "Made in USA".

Among the weapons the US has provided Egypt: F-4 jet aircraft, F-16 jet fighters, armoured personnel carriers, Apache helicopters, antiaircraft missile batteries, and aerial surveillance aircraft, according to the US State Department.

In addition to modernising Egypt's military hardware, the US participates in joint military exercises with the Arab world's most populous nation, including Operation Bright Start, the largest event of its kind in the region.

US wants 'orderly transition'The basis of US assistance to the country is the Egyptian-Israeli peace treaty of 1979, which promised aid to Egypt in return for maintaining the agreement. The US largely views Egypt as a moderating force in the Arab world and a key mediator in the Israeli-Palestinian conflict.

Critics of Washington's policy towards Egypt argue that the financial assistance does not curry favor with the Egyptian people.

Writing for the Carnegie Endowment for International Peace in 2009, Ahmad Al-Sayed El-Naggar said the money "does not aim to strengthen Egyptian military power against any external threat, as this would be contrary to the declared US objective of ensuring Israeli security and maintaining Israeli military supremacy over its Arab neighbors, including Egypt. Instead, this aid is devoted mainly to strengthening the regime's domestic security and its ability to confront popular movements".

Last December, a leaked US cable released by WikiLeaks revealed there is frustration on the part of Egyptian military officials who believe the $1.3bn a year in military aid is not enough.

According to the cable, the deputy assistant secretary of defence for the Middle East, Dr. Colin Kahl, told them it was unlikely that the US would increase its aid given the "difficult financial times".

He did, however, reassure the Egyptian officials that the US government would continue to advocate for current levels of military assistance, the cable states, "and push back on any attempts to condition those funds".